It is earlier known, e.g. from the Swedish published specification 469 080 (9103139-3), to add hydrophobic zeolite to different types of packaging materials, including paper and paperboard. The intention with the addition is to prevent the packaging material from smelling, or to reduce smell to the greatest possible extent and/or to prevent the packaged goods from becoming tainted. For instance, with respect to paperboard packaging materials, it has been feared that the paperboard itself contains ill-smelling and/or ill-tasting substances that are transmitted to the packaged goods, which is why hydrophobic zeolite is added to the paperboard during its manufacture or fabrication. It has also been believed that the added zeolite will block ill-smelling and/or ill-tasting substances that are applied to the paperboard in the after-treatment thereof, for instance when various printing inks are applied to the paper-board.
One drawback with adding the hydrophobic zeolite at the formation of the paperboard, i.e. within the paperboard, or with applying the zeolite in the form of a surface coating on the paperboard is that a large quantity is needed in order to achieve a positive effect. Because hydrophobic zeolite is very expensive, treatment of paperboard with zeolite adds greatly to paperboard manufacturing costs.
In addition, comparatively large quantities of volatile organic compounds in printing inks and other treatment agents are applied when offset printing packaging material, for instance. When the packaging material comprises paperboard of the aforedescribed kind, i.e. paperboard that contains hydrophobic zeolite, problems regarding smell and/or taste still arise, since the zeolite present in the paper-board and forming a part thereof is unable to deal with the large quantities of volatile organic compounds that derive from the printing inks and other treatment agents. In order to satisfy the requirements placed by the final consumers of the paperboard, i.e. the packaging companies, with regard to smell and tainting of the packaged products, it is necessary for the printers, primarily those that use the offset method, to air the printed packaging materials over very long periods of time. This results in high costs and logistic problems on the part of the printers.